by Bonnie Hulkower, New York, New York
This holiday season marks the 111th year of the Christmas Bird Count (CBC). The 111th CBC runs from December 14, 2010 through January 5, 2011. It is the longest running citizen science survey in the world. Thousands of volunteers, "binocular brigades," have already braved winter's chill, rain and snow to record changes in populations of bird species. This tradition was started by ornithologist Frank Chapman on December 25, 1900. Chapman, an officer in the National Audubon Society, suggested starting a Christmas trend of counting birds instead of killing them. Previously, people would spend their Christmas day competitively hunting birds and small mammals. Chapman's group counted and recorded the birds they saw, thus seeding a conservation effort and database that has grown over the last century.
For that 1st count, there were 27 bird observers who participated in 25 places in North America. Since then, the CBC has been held every year. In recent years, there have been more than 60,000 observers involved in over 2,100 places and 17 countries counting more than 2,000 species and 56 million birds. The Audubon Society, who sponsors the CBC, now partners with organizations in other counties such as Bird Studies Canada, the Red Nacional de Observadores de Aves (RNOA, National Network of Bird Observers) and the Instituto Alexander von Humboldt of Colombia.
The CBCs are conducted by volunteers attempting to record every bird they encounter within a designated 15-mile diameter "count circle" on a given calendar day. The volunteers split into small groups and follow assigned routes, which are fairly consistent each year, counting each bird they see. In some count circles, people also watch feeders. Not all the area in the count circles is covered, and not every bird along the routes is identified. The rules prohibit counting birds when retracing one's route, except for species the group hasn't seen before, in an attempt to avoid double counting. Flocks are difficult to count precisely, so an expert will estimate the number for that species during the morning or evening and usually no individuals are counted at other times. Accuracy is also assured by having new volunteers join an established group that includes at least one experienced birdwatcher.
The volunteers come for the fun, but the surveys are actually valuable for science and used in peer reviewed studies. The surveys (available back to 1900) are added to a growing database that provides information to researchers who study winter bird populations across North America. Local CBC data are then sent to the National Audubon Society. In aggregate, they're used to monitor the fluctuating populations of species, by extension the health of the birds and their environment, and what needs to be done to protect them. The data informs the U. S. State of the Birds Report, issued by the Department of the Interior each year. CBC analyses also reveal how some species have been experiencing declines. For example, the Common Grackle has declined by 60% over the past 40 years. In parts of California, the yellow-billed cuckoo, clapper rail, willow flycatcher and burrowing owl have been in decline, largely because of loss of wetlands and salt marsh habitats. But on occasion, the CBCs also show recoveries... read more story at TreeHugger.com